# File lib/pixels.rb, line 382 382: def row_offset(y) 383: if y < 0 or y >= @height 384: raise ArgumentError.new("y-coordinate #{y} out of range") 385: end 386: 387: # Flip the vertical axis when (0, 0) is in the lower-left 388: # corner of the image. 389: if @origin == :LOWER_LEFT 390: y = (@height-1) - y 391: end 392: 393: return @image_data_offset + @bytes_per_row * y 394: end